THE MATH OF FITNESS By Eric Kim
How is Math Relevant to Fitness? Math helps us to maintain our exercise routines. Math is used to calculate short- term and long- term goals. Math is used to measure our growth in fitness levels. Math can be used to perfect exercise form. Math can tell us when to take a water break.
Numbers & Formulas in Relation to Fitness
BMI (Body Mass Index) BMI is a used to measure how overweight or obese an individual may be. It is calculated from your height and weight. BMI is an estimate of body fat and a good gauge of your risk for diseases that can occur with more body fat. The Higher BMI, the higher your risk for certain diseases such as cardiovascular disease, high blood pressure, type 2 diabetes, gallstones, breathing problems, and certain types of cancers.
Limits of BMI It may overestimate body fat in athletes and others who have a muscular build. It may underestimate body fat in older individuals and others who have lost muscle mass.
How To Calculate BMI Standard Formula BMI = Weight (kg) Height (m) 2 Weight Conversion: wt. in lbs 2.2 = wt. in kg Height Conversion: ht. in inches 0.0254 = ht. in meters
BMI Categories Underweight = < 18.5 Normal weight = 18.5 24.9 Overweight = 25 29.9 Obese = 30 or greater
Body Fat Percentage Common ways of measuring body fat %: Skin Fold Caliper Bioelectric Impedance Analysis Anthropometric (Girth Measurements) Hydrostatic Weighing DEXA Scan (Dual Energy X- ray Absorptiometry) Variability in measurements & accuracy Variability in costs and accessibility
Body Fat Calculations Terminology: Lean Body Mass (LBM) Fat Mass (FM) Body Weight (BW) Desired Body Weight (DBW) Desired Body Fat Percent (DBF%) Percent Body Fat (%BF)
Body Fat Calculations Fat Mass = % Body Fat Body Weight Example: % Body Fat = 8% Body Weight = 160 lbs Fat Mass = 0.08 160 = 12.8 lbs Lean Body Mass = Body Weight Fat Mass Example: Lean Body Mass = 160 12.8 = 147.2 lbs
Body Fat Calculations % Body Fat = Fat Mass Body Weight Example: % Body Fat = 12.8 160 = 0.08 = 8% Body Fat Desired Body Weight = LBM (1 Desired Body Fat %) Example: DBW = 147.2 (1 0.06) = 156.6 lbs Desired Body Fat % = 1 (LBM DBW) Example: DBF% = 1 (147.2 156.6) = 0.06 = 6% Body Fat
Basal Metabolic Rate (BMR) BMR is the minimum calorific requirement needed to sustain life in a resting individual. Factors that determine BMR: Genetics Gender Age Muscle Mass Body Temperature Exercise
Calculating Your BMR Harris Benedict Equation: Women: BMR = 655 + (4.35 wt. in lbs.) + (4.7 ht. in inches) (4.7 age) Men: BMR = 66 + (6.23 wt. in lbs.) + (12.7 ht. in inches) ( 6.8 age)
Calculating Your BMR Activity Level Daily Calories Needed Sedentary BMR 1.2 Light Exercise (1-3 days/week) BMR 1.375 Moderate Exercise (3-5 days/week) BMR 1.55 Intense Exercise (6-7 days/week) BMR 1.725 Very Intense Exercise (2 extreme workouts per day) BMR 1.9
Heart Rate Resting Heart Rate (RHR) is your heart rate upon waking up in the morning. To measure your RHR, use your index and middle finger to place on either your radial artery on your wrist or at your carotid artery in your neck. Next, count the number of beats in 10 seconds and multiply that number by 6. Maximum Heart Rate (HR max ) is the highest heart rate an individual can achieve through exercise stress.
Heart Rate Formulas HR max = 220 age Heart Rate Reserve (HRR) = MHR RHR Karvonen Formula: (HRR % Intensity) + RHR = Target Heart Rate (THR)
Heart Rate Training Zones Zone 1 Light Exercise 50% 60% Zone 2 Moderate Exercise 60% - 70% Zone 3 Endurance Training 70% - 80% Zone 4 High Performance Training 80% - 90%
Rate of Perceived Exertion (RPE) The RPE Scale is used to measure the intensity of your exercise. The RPE scale runs from 0-10. The higher the number on the scale, the higher the intensity of the exercise
Conclusion Although maintaining fitness is not commonly thought of as a quantitative activity, math is incorporated in all areas of exercise. Math gives individuals a tangible way of recording their success and growth in fitness. Math can motivate individuals to stay consistent with their exercise routines.
References http://www.nhlbisupport.com/bmi/ http://www.nhlbi.nih.gov/health/public/heart/obesity/lose_wt/ risk.htm#limitations http://www.acefitness.org/blog/112/what- are- the- guidelines- for- percentage- of- body- fat/ http://www.acefitness.org/fitnessqanda/fitnessqanda_display.aspx?itemid=325 http://www.builtlean.com/2010/07/13/5- ways- to- measure- body- fat- percentage/ http://www.bmi- calculator.net/bmr- calculator/bmr- formula.php http://www.shapefit.com/basal- metabolic- rate.html
References Continued http://www.cdc.gov/physicalactivity/everyone/measuring/ heartrate.html http://www.acefitness.org/newsletters/archive/ 2010sapsurveyresponse/Math- Formulas- and- Tips.pdf http://www.livestrong.com/article/172000- how- to- calculate- heart- rate- training- zones/ http://my.clevelandclinic.org/heart/prevention/exercise/ rpe.aspx